Embodiments of the present invention use bending wave loudspeakers, particularly resonant bending wave speakers of the kind known as distributed mode acoustic radiators, as taught in International application WO97/09842 and corresponding U.S. Pat. No. 6,332,029 the latter of which is herein incorporated by reference. It is known from WO 97/09842 and corresponding U.S. Pat. No. 6,332,029 and other publications (e.g. WO97/09846, WO99/08479 and WO00/33612 which correspond to granted U.S. Pat. No. 6,031,926, and pending U.S. application Ser. Nos. 09/497,655 and 09/450,754 in the name New Transducers Limited) to apply one or more exciters to a bending wave panel for energizing bending waves in the panel. The locations of the exciters may be chosen with consideration for modal drive coupling, moderating directional effects or adjusting behaviour through the coincidence frequency region.
This invention is particularly concerned with acoustic devices in the form of resonant acoustic radiator loudspeakers for use in passenger vehicles such as automobiles, aircraft, boats, railway trains, etc., and to vehicles incorporating such loudspeakers. There are various International applications of the present applicant which discuss the application of such bending wave speakers in passenger vehicles, for example WO 97/09844, WO 98/42536, WO 99/11490, WO 00/45616 and WO 00/48425. The corresponding U.S. application Ser. Nos. 09/029,349, 09/398,057, 09/501,770 (now U.S. Pat. No. 6,377,695), Ser. Nos. 09/494,304 and 09/928,924 are herein incorporated by reference.